A randomized controlled trial of the effects of isolated lumbar extension exercise on lumbar kinematic pattern variability during gait in chronic low back pain
Background: Chronic low back pain (CLBP) is a multifactorial condition with a variety of symptoms, one of which is abnormal gait. The lumbar spine and its musculature are important in controlling gait, and in CLBP the lumbar extensors are often deconditioned. Because of this specific isolated lumbar extension, exercise often is recommended. It was therefore of interest to examine its effects of upon gait variability. Objective: To examine the effects of isolated lumbar extension resistance training on lumbar kinematic variability during gait in participants with CLBP. Design: Randomized controlled trial. Setting: University Health, Exercise and Sport Science Laboratory. Participants: Twenty-four participants with nonspecific CLBP. Interventions: Participants were randomly allocated to a 12-week isolated lumbar extension exercise intervention (1×/week performing a single set to momentary muscular failure using a load equal to 80% max tested torque) or nontraining control period. Main Outcome Measurements: Lumbar kinematics during gait, including angular displacement, kinematic waveform pattern (CVp), and offset (CVo) variability, were examined via 3-dimensional analyses. Results: No significant changes in displacement or CVo were found as a result of the intervention; however, a small but significant reduction in sagittal plane CVp (−20.90 ± 3.53%, effect size = 0.48, P = .044) occurred, indicating improved motor pattern replication through this movement plane. Conclusions: Considering the role of the lumbar extensors in gait, and their common deconditioning in CLBP, an isolated lumbar extension resistance exercise intervention may reduce gait variability. These results suggest isolated lumbar extension exercise may specifically reduce sagittal plane variability, indicating improved motor pattern replication through this movement plane, perhaps attributable to the plane of movement used during the exercise.